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"When the Hasmoneans overpowered and defeated the Greeks, they
searched and found only one cruse of oil, which lay with the seal of
the Kohen Gadol." (Shabbat 21b)

QUESTION:

What assurance did they have that the cruse was not touched
by any of the Greek soldiers?

ANSWER:

This question is raised by Tosafot (ibid.), and answered,
that it was buried in the ground, and thus the Greeks did
not see it or know of its existence. A difficulty with this
explanation is that there is no allusion to this fact in the
Gemara. Moreover, if so, why was it necessary to have a seal
on it?

Careful analysis of the terminology used in the Gemara,
prompts one to ask:

The Kohen Gadol was not in charge of making oil. Why would
his seal be on the cruse?

Grammatically, instead of saying "it lay" it should have
said, "it was sealed."

From this we may deduce that when the Hasmoneans entered the
Beit Hamikdash, their eyes beheld a fascinating phenomenon.
They saw one cruse of oil, and it was laying together with the
very valuable golden signet ring of the Kohen Gadol. They
surmised, that undoubtedly, nobody had come into this area,
because he definitely would have stolen the ring. Therefore,
they confidently assumed that the cruse was not defiled by any
of the Greeks, and fit for the Menorah kindling.